Method and apparatus for producing cotton wool products

ABSTRACT

The invention relates to a method for producing a wadding product, in particular for producing wadding pads for cosmetic purposes, comprising the following steps:
         preparing a preliminary non-woven mat which is made at least predominantly of cotton fibers,   compacting said preliminary non-woven mat by using a plurality of hot high-pressure gas jets.       

     For the apparatus it is provided that the device for compacting ( 2, 12′, 14, 15, 15′, 16, 16 ′) the preliminary non-woven mat ( 7 ) comprises a device for subjecting the preliminary non-woven mat ( 7 ) to hot gas at a high pressure.

The invention relates to a method for producing wadding products and a device for performing said method according to the precharacterizing part of the device claim and the method claim, respectively.

EP 1 310 226 B1 describes the production of a cosmetic wadding pad from a random-fiber non-woven mat of bleached cotton fibers by use of water-jet needling. At least one surface of the pad comprises fine grooves generated by water-jet needling. A similar article is described in EP 1 106 723 B1.

By the water-jet needling, a large quantity of humidity is introduced into the wadding, which will have to be removed again by a subsequent drying process. Further, the drying process will cause the properties of the pad to change in a certain extent. In many applications, a wadding pad having a too firm, hard surface is perceived as unpleasant.

From EP 1 553 222 A1, an apparatus is known for subjecting a non-woven sheet to superheated steam. Application of the steam is performed by a hollow body extending across the width of the sheet which is to be treated. On its bottom side, the hollow body which can be fed with superheated steam is provided with a plurality of exit nozzles from which hot steam will be directed onto the sheet, while the sheet is being passed through below the body at a close distance.

DE 10 2008 031 278 A1 describes the production of an absorptive product by use of steam needling. The product which is to be produced comprises cellulose fibers and/or other natural fibers which will be laid onto a non-woven of staple fibers that has been prefabricated by steam needling, or onto a spunbonded non-woven.

Further, DE 10 2008 007 804 A1 describes a non-woven with liquid-absorbing components which is produced with application of steam needling. Finally, DE 10 2008 007 796 A1 describes the application of jets of superheated steam for increasing the fluffiness of a to-be-generated product. There is performed a compacting of synthetic fibers or filaments.

It is an object of the present invention to improve a method and a corresponding device for producing a wadding product.

The above object is achieved by the features defined in the method claim and the device claim, respectively. Advantageous variants of the inventions are defined in the respective subclaims.

According to the invention, it is provided that the preliminary non-woven, made substantially of cotton fibers, is compacted by application of high-pressure hot gas. Herein, the preliminary non-woven mat can consist of bleached cotton fibers by 100%.

Preferably, also an admixture of other natural fibers can be provided. Particularly fibers of polylactides and respectively polylactic acid can be admixed, wherein these fibers, due to their thermoplastic properties and the influence of superheated steam, will result in additional strength in the wadding pad.

The invention particularly useful for the production of wadding pads for cosmetic purposes. Use is made of the surprising recognition that, by application of high-pressure hot steam jets, even a preliminary non-woven mat made of 100% cotton fibers can be compacted. By the high-pressure hot steam jets, it is accomplished that, on the one hand, a slight interlacing or entanglement of the fibers will be caused by the pulse effect of the steam jets and that, on the other hand, the hot superheated steam will cause a slight thermoplastic bonding of the fibers. In this manner, there is generated a very fluffy product which nonetheless can have sufficient strength for the intended use. The strength is in any case higher than the strength of the pure preliminary non-woven mat. Further, there will not be generated a surface of a rigid tactile feel but rather a surface feeling like a closed surface, as is the case in pure calandering and respectively in compacting by water-jet needling of a preliminary non-woven mat made of wadding.

According to a preferred variant of the production method, there is provided a compacting of a preliminary non-woven mat provided in a plurality of layers.

In the invention, it is preferred that the compacting of the non-woven mat by superheated steam is performed at a temperature of about 220° (Celsius). For this purpose, the steam-needling unit comprises steam exit openings having a diameter of 0.03 mm and arranged at distances of 1.5 mm. The steam-needling unit can be designed as a tube comprising the steam exit openings in the form of drilled holes. Preferably, the steam exit openings can be arranged in two or more rows extending parallel to each other. By an offset of the steam exit openings in the individual rows, correspondingly higher needling densities can be reached. Further, the plural number of steam exit openings will result in a sufficiently high introduction of heat into the product.

In the inventive device for performing the production method, there is included a means for providing a preliminary non-woven mat in the form of a fiber sheet, the fibers of said preliminary non-woven mat substantially consisting of cotton fibers. Preferably, in this regard, use is made of a cotton carding machine, optionally followed by a means for longitudinal folding and folding-together of the preliminary non-woven mat into a plurality of layers.

Thereafter, the preliminary non-woven mat provided in one or a plurality of layers will be supplied, via a compacting means, to a first steam treatment performed by a steam needling unit. The compacting means preferably comprises two screen belts (endless belts) converging at an angle, one of said screen belts carrying the preliminary non-woven mat and the other screen belt pressing the non-woven mat, while, subsequently, the first application of steam is performed through the latter screen belt which holds the non-woven mat in a pressed state.

Said first application of steam can be followed by further steam applications whereby steam will be applied to the non-woven mat and the fiber sheet from one or both sides. Especially by steam application performed from both sides, a uniform introduction of heat is guaranteed.

Preferably, the application of steam onto the fiber sheet is performed in the area of a needling drum (screen drum, suction drum) deflecting the sheet, said drum being provided with an internal suction drain site for the steam.

An advantageous variant of the invention is obtained if a heat exchanger recovers the excess energy of the sucked steam and this energy is fed to a steam processing site. In this regard, it is preferably provided that the entrance duct to the steam generator is arranged upstream of a heat exchanger which is in thermal contact with a conduit downstream of a suction site. By means of this heat exchanger, the fresh water supplied to the heat exchanger is preheated. Herein, depending on the machine configuration, the heat exchanger can be arranged directly in the suction drum, downstream of the suction drain line of the suction drum and upstream of the condensate separator, or downstream of the condensate separator and the suction pump.

An exemplary embodiment of the invention will be explained hereunder with reference to the drawings. In the drawings, the following is shown:

FIG. 1 is a lateral view of a larger system of a steam-needling device wherein a deflection roller of the first endless belt is formed as a needling drum,

FIG. 2 is a view of the system according to FIG. 1, wherein the deflection roller of the first endless belt is used for a first application treatment of the fiber sheet, while further steam applications will be performed on a following deflection roller, designed as a takeover roller, of the second endless belt and thus will compact the fiber sheet from the other side, and

FIGS. 3 and 4 are views of two embodiments of the heat recovery according to the invention,

FIG. 5 is a view of a further embodiment of a system for application of steam onto a fiber sheet.

A steam needling unit with a needling drum 2 is shown as arranged in a frame 1. Said needling drum 2 (screen drum) comprised a suction means as illustrated in greater detail in FIGS. 3 and 4. The unit shown in FIG. 1 is normally the first unit of a larger needling system wherein, thus, there can follow a plurality of further needling drums which are will be contacted by the fiber sheet in a meandering manner and by which the fiber sheet will then be treated on both sides (in this regard, cf. FIG. 2).

This unit comprises a first endless belt 3 (screen belt) which is deflected and held tensioned by a plurality of rollers 5 arranged for rotation in a holding rack 4 and by the needling drum 2. On this endless belt 3, there is conveyed, in the direction of arrow 6, a batt (fiber sheet 7) of bleached cotton fibers that is supplied by a carding machine. This batt has no substantial strength and will be laid directly onto the endless belt 3 by the carding machine (not shown). Depending on the required volume of the product which is to be generated, one or a plurality of layers of batt can be supplied for use. This can be performed e.g. by longitudinally folding the batt supplied by a carding machine.

The needling drum 2 serves for deflection of endless belt 3 as well as for pretreatment by steam and respectively for needling by steam. This means that the needling drum is formed as a permeable drum (screen drum) which in its interior is provided with a suction drain 2′. The direction of the suctional removal is indicated by the arrows 8.

Assigned to the first endless belt 3 is a further endless belt 9, running in the opposite sense, in such a manner that the working strand 3′ of the first endless belt 3 is arranged opposite to the working strand 9′ of the second endless belt, while, there, the strands 3′,9′ rotate in the same direction and in this region, conically run toward each other (compacting region for the batt—fiber sheet 7). This in turn is effected by a plurality of rollers 10-12 of endless belt 9 which are arranged for rotation on the holding rack 13 fastened to frame 1.

Two of the rollers of the second endless belt 9, namely rollers 11 and 12, are directly assigned to the needling drum 2 of the first endless belt 3. This means that the rollers 11 and 12 are operative to press the tensioned endless belt 9 against the endless belt 3 and then against the needling drum 2. For this purpose, these rollers are arranged closely adjacent to each other and leave only so much space between them that the steam nozzle unit (the stream nozzle bar) 14 can be advanced to endless belt 9. In this manner, the supplied fiber sheet which is advanced by the strand 3′ of endless belt 3, will not only be slowly compacted between the endless belts 3 and 9 but will also be pressed onto the needling drum 2. In this state, the fiber sheet 7 is pretreated by the first steam nozzle unit 14 and then can be further needled.

In the embodiment according to FIG. 1, this will be performed directly on this needling drum 2 in that the endless belt 9 is deflected in the upward direction by roller 12 so that the upper side of the fiber sheet 7 will have been freed from the endless belt 9. Downstream of said deflection of endless belt 9, the needling drum 2 has two further steam nozzle units (steam nozzle bars) 15,16 assigned to it in an axially parallel arrangement, said further steam nozzle units serving to generate a slight intertwining of the fibers which is achieved by the pulse effect of the steam. Then, while supported by endless belt 3, the fiber sheet will be further transported and passed on to a further treatment organ 17 and will thus be detached from endless belt 3.

The same principle is maintained if, in the embodiment according to FIG. 2, the roller 12 of second endless belt 9 is designed as a takeover roller 12′ and at the same time as a needling drum. Herein, in correspondence thereto, steam nozzle units (steam nozzle bars) 15′ and 16′ are assigned to the takeover roller 12′, formed as a screen roller, of endless belt 9. In this embodiment, the wetting is performed by said bar 14 and the first needling by said nozzle bars 15′,16′ onto different surfaces of the fiber sheet.

The steam nozzle units (steam nozzle bars) 14,15,15′,16,16′ comprise, on their underside facing toward the needling drum 2 and respectively the takeover roller 12′, a plurality of steam exit orifices extending across the width of the fiber sheet. Said steam exit orifices can be arranged in one or a plurality of mutually parallel rows.

FIG. 3 depicts one of the steam nozzle units 14,15,15′,16,16′ according to FIG. 1 and respectively 2 which via a conduit is supplied with superheated steam from a superheater 20. The steam is provided by a steam generator 30 arranged upstream of said superheater unit.

By means of the steam nozzle unit 14,15,15′,16,16′, application of steam onto the fiber sheet is performed as described in connection with FIGS. 1 and 2. During the steam application/steam needling, the fiber sheet is carried by a steam-permeable needling drum 2,12′ (screen drum) (FIGS. 3 and 4). In the interior of the rotatably supported drum 2,12′, a suction drain (suction chamber) 50 is arranged which is connected to a suction line 60 and a condensate separator 70. The liquid components of the components of the sucked steam which are captured in said condensate separator 70 (suction chamber 50) will be discharged via a drain 80. Via a suction line 90, the gaseous phase of the contents of condensate separator 70 is connected to a suction pump 100. The steam removed by suction will be discharged via a venting line 110.

The feed line 120 (fresh water) for the steam generator 30 is arranged upstream of a heat exchanger 130 which is tightly thermally coupled to the venting line 110 of suction pump 100. Thus, by means of the thermal energy of the steam suctionally removed by pump 100, the fresh water of feed line 120 will be preheated and be fed, with corresponding temperature, to the steam generator 30. The energy demand of the steam generator is thus reduced corresponding to the preheating of the supplied fresh water.

In the embodiment according to FIG. 4, the components bearing the reference numerals 2, 12′, 14, 15, 15′, 16, 16′, 20-110 have the same designations and functions as in the example according to FIG. 3. In difference thereto, the heat exchanger 130A with the feed line 120A for fresh water is thermally coupled to suction line 60 between suction chamber 50 and condensate separator 70. Thereby, the fresh water of feed line 120A can be brought to a higher temperature—the energy saving of the steam generator will be correspondingly higher.

According to a non-illustrated embodiment of the invention, the heat exchanger for heating the fresh water is directly integrated into drum 2,12′. By the high temperatures prevailing therein, the degree of energy recovery will be correspondingly higher.

In the embodiment according to FIG. 5, the fiber sheet 7 will be laid onto the working strand 3′ of a first endless belt 3 formed as a screen belt. The endless belt 3 is tensioned about deflection rollers 5. The second endless belt 9, again formed as a screen band, rotates in the opposite sense to endless belt 3 and is tensioned about deflection rollers 10. The fiber sheet 7 transported in the direction of arrow 6 will first be compacted between the conically converging working strands 3′,9′ of the endless belts 3,9 and then be held pressed in the region of the parallel endless belts 3,9.

In this region where the compacting takes place, two steam nozzle units 14,15 formed as tubes are arranged below the endless belt 3, said steam nozzle units comprising steam exit openings in the form of bores. Assigned to each steam nozzle unit 14,15 is a suction chamber 50 above endless belt 3. In this region, the fiber sheet 7 held pressed between the endless belts will be subjected to hot steam from below. Downstream of the region of the compacting, i.e. where the fiber sheet 7 is only resting on the endless belt 3, two further tubular steam nozzle units 14′,15′ are arranged above fiber sheet 7. The appertaining suction chambers are arranged below the endless belt 3 supporting the fiber sheet 7. In this manner, the fiber sheet 7 is subjected to an introduction of heat occurring in a uniform manner from both sides.

LIST OF REFERENCE NUMERALS

-   1 frame -   2, 12′ drum, needling drum, screen drum -   3 endless belt -   3′ working strand -   4 holding rack -   5 roller, deflection roller -   6 arrow -   7 fiber sheet, fibrous non-woven, wadding -   9 endless belt -   9′ working strand -   10 roller -   11 roller -   12 roller -   13 holding rack -   14, 15, 15′, 16, 16′ steam nozzle unit -   20 superheater -   30 steam generator -   50 suctional removal (suction chamber) -   60 suction line -   70 condensate separator -   80 drain -   90 suction line -   100 suction pump -   110 venting line -   120A feed line (fresh water) -   120A feed line (fresh water) -   130 heat exchanger -   130A heat exchanger 

1. A method for producing a wadding product for cosmetic purposes, said method comprising the following steps: preparing a preliminary nonwoven mat which is made at least predominantly of cotton fibers, and compacting said preliminary nonwoven mat by using a plurality of hot high-pressure gas jets.
 2. The method of claim 1, wherein the preliminary nonwoven mat is made of 100% cotton fibers.
 3. The method of claim 1, wherein the preliminary nonwoven mat is made largely of cotton fibers and of a portion of further thermoplastic natural fibers.
 4. The method of claim 2, wherein said further natural fibers are made of polylactides and polylactic acids.
 5. The method of claim 1, wherein the compacting is performed by steam needling with superheated steam.
 6. The method of claim 5, wherein the temperature of the hot steam is about 220 degrees Celsius.
 7. The method of claim 5, wherein the application of hot steam is performed at a pressure of 10-25 bar.
 8. The method of claim 1, wherein the application of hot gas and hot steam is performed in a pressed, precompacted state of the preliminary nonwoven mat.
 9. A device for producing wadding products for cosmetic purposes, said device comprising: means for making a preliminary nonwoven mat which at least for the major part consists of cotton fibers, downstream of said means, a means for compacting said preliminary nonwoven mat, for performing the method according to claim 1, wherein the means for compacting the preliminary nonwoven mat comprises a means for treating the preliminary nonwoven mat with high-pressure hot gas.
 10. The method of claim 9, wherein said means for compacting the preliminary nonwoven mat is a steam needling device.
 11. The method of claim 10, wherein said steam needling device has a means for suctional removal.
 12. The method of claim 10, wherein said steam needling device cooperates with a needling drum.
 13. The method of claim 10 wherein said steam needling device has a steam generator and an superheater.
 14. The method of claim 13, wherein said steam generator is connected to a heat exchanger in thermal contact with said means for suctional removal.
 15. The method of claim 14, wherein said heat exchanger is coupled to a line arranged downstream of said means for suctional removal. 